"Wavefronts" in the aorta--implications for the mechanisms of left ventricular ejection and aortic valve closure.

Our understanding of the way the left ventricle ejects blood into the aorta has been advanced by considering aortic flow in terms of the elemental haemodynamic forces, compression and expansion wavefronts. The pattern of aortic wave intensity indicates that the contracting and relaxing left ventricle generates compression and expansion waves and that it is these, rather than the waves reflected from the arteries, that dominate ejection in the normal cardiovascular system. The wave intensity is a novel haemodynamic variable, with the potential to provide information about heart-vessel coupling and the fluid dynamic consequences for cardiac output of myocardial contraction and relaxation. This information should now be realised in experimental studies of the integrated circulation in health and in disease.